Stabilized medicinal white oils



Patented Nov. 28, 1944 UNITED STATES PATENT OFFICE STABILIZED MEDICINAL WHITE OILS Jacob Faust, Belleville, N.'J., and Henry Sonneborn, 11!, Baltimore, Md., assignors to L. Sonneborn Sons, Inc., a corporation of Delaware No Drawing. Application November 10, 1941, Serial No. 418,612

8 Claims.

The first stage of autoxidative deterioration of medicinal white oils is the formation of peroxides and the time which elapses until the first peroxide formation can be observed is regarded as a criterion of the stability of a given product. Under ordinary conditions such time element is expressed in weeks or months but by subjecting a medicinal white oil to high temperatures the time elapsing until the first traces of peroxide formation appear may be expressed in minutes and is oil to be treated in small amounts sufilcient to raise the normal induction period of the same and to substantially efiectuate thereby a stabilization then commonly termed in petroleum refining 4 technology the induction period of the medicinal white oil and serves as a practical measure for the relative stability of the product. One common practice for the determination of the induction period is to heat the medicinal white oil to be tested in quantities of 10 co. in stoppered test tubes in an oil bath kept at 300 F. for convenient intervals, as a rule multiples of five minutes. The peroxide test as such may be carried out by shaking the oil to be tested with an aqueous acetone solution of ferrous thio-cyanate which will show a red coloration at the first sign of peroxide formation as the result of the conversion of the ferrous to ferric thio-cyanate. Where in the specification and claims, therefore, we use the term induction period in connection with a medicinal white oil inherently subject to autoxidation, we mean to define thereby the period which elapses until the first traces of peroxide formation appear in the medicinal white oil while the same is heated at a temperature of approximately 300 F,

We have discovered that it is possible to substantially stabilize medicinal white oils and substantially inhibit any inherent autoxidation and resulting deterioration of such products by the addition of comparatively small amounts of tocopherol.

In the practical application of our invention, the tocopherol is dissolved in the medicinal white to the desired extent. Though substantially absolute and permanent stabilization may be obtained. it wfll in many cases suflic for practical purposes to achieve a stabilization equivalent to a material increase in the induction period of the untreated medicinal white oil. As a rule, additions of .00005% and in some oases as low as .00001% of tocopherol give good results. Maximum efiiciency is usually obtained with additions of approximately .005% tocopherol and normally no further increase in induction period is accomplished by higher amounts.

In manufacturing a commercial product, however, we prefer to obtain an induction period of at least 30 minutes which is equivalent'to a stabilization under atmospheric conditions and even constant exposure to sunlight for a period in excess of six months which in most cases is regarded as sufiicientl stable and we have found additions of .00001% to .001% sufllcient for such purpose.

The term tocopherol" as used herein is employed generically and is intended to include within its scope tocopherol derivatives and homologues of equivalent action and is particularly designated to include a tocopherol, ,3 tocopherol and 'y tocopherol as well as mixtures of any two or more of these. As a rule no material differenee in comparative efliciency between these products is observed though in some cases the 1 product is a more potent stabilizer than the a and 5 products.

The following tabulations are illustrative of practical embodiments of our invention but are in no way to be taken as indicative of the scope Microgrsms I d t! atooopherol n per cc. period m white oil minutes Medicinal white il Sayb. 350 100 F.

TABLE II Medicinal white oil Sayb. 350 100 F. Induction period: minutes Micrograms a tocggsierol g gi fi g cc. v hite oil minutes TABLE m Medicinal white oil Sayb. 350 100 F. Induction period: 5 minutes micrograms a tociigoherol gfigf:

per cc.

white oil mmutes TABLE IV induction period: 5 minutes Micrograms p tocogoherol gggg g per 1 cc.

white oil mmutes TABLE V Medicinal white oil sag/b. 350 100 F. Induction period: 5 minutes Micrograms 1 tocopherol per 100 cc. white 011 m u s It will be seen from the foregoing tables that great stability can be imparted to medicinal white oils by the addition of relatively minute amounts of tocopherol. For all practical purposes, however the concentration of tocopherol needed to insure adequate stability were in all cases sufficiently small so as to not aflect the purity of the medicinal white oils as Judged by the U. S. Pharmacopoeia "Acid Test."

The foregoing description is by way 01 illustration and not of limitation'and we are not to be limited to any details but only by the appended claims in which we have endeavored to claim broadly all inherent novelty.

.. We claim: 1. A medicinal white oil composition comprising a medicinalwhite oil, inherently subject to autoxidation, having normally a low induction period and a small amountof tocopherol sufficient to raise the normal induction period of said white oil.

' 2. A medicinal white oil composition comprising a medicinal white oil, inherently subject to autoxidation, having normally an induction pe rind of less than thirty minutes and a small amount of tocopherol, sufficient to raise the normal induction period oisaid medicinal white oil to at least thirty minutes.

3. A medicinal white oil composition comprising a medicinal white oil, inherently subject to autoxidation, having normally a low induction period and .00001% to .005% tocopherol.

4. A medicinal white oil composition in accordance with claim 3 in which said tocopherol is present in amount from .00005% to .005%.

5. In the stabilization of medicinal white oils,

the step which comprises raising the normally low induction period of a medicinal white oil, inherently subject to autoxidation by incorporation therein .00001% to .005% tocopherol.

6. A medicinal white oil composition in accordance with claim 2 in which said tocopherol is a tocopherol present in amount insuincient to affect the standard U. S. P. acid test.

7. A medicinal white oil composition in accordance with claim 2 in which said tocopherol is p tocopherol present in amount insuflicient to affect the standard U. S. P. acid test.

8. A medicina1 white oil composition in accordance with claim 2 in which said tocopherol is 1 tocopherol present in amount insuflicient to ailect the standard U. S. P. acid test.

HENRY SON'NEBORN, III. JACOB FAUST. 

